package com.wugui.datax.admin.filter;

import java.io.IOException;
import java.util.Collections;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.extension.api.R;
import com.wugui.datax.admin.exception.TokenIsExpiredException;
import com.wugui.datax.admin.util.JwtTokenUtils;

/**
 * Created by jingwk on 2019/11/17
 */
public class JWTAuthorizationFilter extends BasicAuthenticationFilter {

	public JWTAuthorizationFilter(AuthenticationManager authenticationManager) {
		super(authenticationManager);
	}

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
			throws IOException, ServletException {

		String tokenHeader = request.getHeader(JwtTokenUtils.TOKEN_HEADER);
		// 如果请求头中没有Authorization信息则直接放行
		if (tokenHeader == null || !tokenHeader.startsWith(JwtTokenUtils.TOKEN_PREFIX)) {
			chain.doFilter(request, response);
			return;
		}
		// 如果请求头中有token，则进行解析，并且设置认证信息
		try {
			SecurityContextHolder.getContext().setAuthentication(getAuthentication(tokenHeader));
		} catch (TokenIsExpiredException e) {
			// 返回json形式的错误信息
			response.setCharacterEncoding("UTF-8");
			response.setContentType("application/json; charset=utf-8");
			response.getWriter().write(JSON.toJSONString(R.failed(e.getMessage())));
			response.getWriter().flush();
			return;
		}
		super.doFilterInternal(request, response, chain);
	}

	// 这里从token中获取用户信息并新建一个token
	private UsernamePasswordAuthenticationToken getAuthentication(String tokenHeader) throws TokenIsExpiredException {
		String token = tokenHeader.replace(JwtTokenUtils.TOKEN_PREFIX, "");
		boolean expiration = JwtTokenUtils.isExpiration(token);
		if (expiration) {
			throw new TokenIsExpiredException("登录时间过长，请退出重新登录");
		} else {
			String username = JwtTokenUtils.getUsername(token);
			String role = JwtTokenUtils.getUserRole(token);
			if (username != null) {
				return new UsernamePasswordAuthenticationToken(username, null,
						Collections.singleton(new SimpleGrantedAuthority(role)));
			}
		}
		return null;
	}

}
